The Rev. Salvatore Cordileone, known for his strong support of California's same-sex marriage ban, was officially appointed late last week by the Vatican as the archbishop of San Francisco.

Cordileone, 56, had been the presiding bishop of Oakland, The Associated Press reported, but will now take up one of the top bishop positions in the Unites States when he replaces Archbishop George Niederauer in October. The San Francisco Archdiocese serves 400,000 members in the city and neighboring Marin and San Mateo counties.

Currently, same-sex marriage is not legally recognized in California, and Cordileone played an important role four years ago with the passage of Proposition 8, which ended the state's short-term status when it granted marriage licenses to homosexual couples. Besides supporting the bill, the bishop also helped raise money to bring it to the ballot – voter records indicate he made a personal donation of at least $6,000 toward the ban.

Cordileone was also appointed last year as chairman of the U.S. Conference of Catholic Bishops' Subcommittee for the Promotion and Defense of Marriage, which seeks to keep the definition of marriage as a union solely between one man and one woman.

The bishop has made it clear that defending marriage is not simply a matter of faith, and in an interview last year he expressed that the current push for same-sex marriage is "a very serious social experiment that will have dire consequences."

"Marriage can only come about through the embrace of a man and a woman coming together," he added at a conference this past Friday at St. Mary's Cathedral in San Francisco. "I don't see how that is discriminatory against anyone."

His appointment to archbishop, however, does not sit well with gay rights groups who see the move as further attempts by the Vatican to oppress homosexual people in the country seeking to be included in the definition of marriage.

"While LGBT Catholics and their allies have worked relentlessly to create welcoming environments, the appointment of Bishop Cordileone sends a chilling message that, in the eyes of the hierarchy, same-sex relationships are not worthy of equal dignity and respect," said Human Rights Campaign President Chad Griffin.

Same-sex marriage remains a dividing issue among the Catholic community. Although the Vatican supports the traditional definition of marriage, a 2012 poll found that 59 percent of Catholic respondents in the United States approve of same-sex couples being granted legalized marriage.